It is understood that Armed Forces planners are looking at the possibility that a new global financial crash could undermine the defence forces of key British allies.

The head of the Armed Forces warned that economic issues pose a “strategic risk” to Britain.
Senior British commanders and officials are concerned that US plans to cut defence spending will be followed by other allies in Europe and elsewhere.

Reductions in allied military capabilities could put a greater burden on Britain’s stretched forces in Afghanistan and elsewhere, it is feared.

The military planning work has come to light after The Daily Telegraph disclosed last month that British embassies in the eurozone have been told to prepare emergency plans for the demise of the euro and the possible civil disorder that could follow.